“The word “THINK” painted large scale on the facade of a building in a neighbourhood of the city of Katowice (Poland). Katowice Street Art Festival 2013.” This intervention (by the Spanish artist SpY) is a reflection about how public spaces present opportunities and can be used to encourage the inhabitants of the cities to THINK about the urban landscape. Along with that, this example of cultural sustainability focus on how the collective spaces express the identities of the people in a city. (photos by Spy)